gas welding safety

7/24/2019 Gas Welding Safety

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as welding&as welding&

cutting Plant

utting Plant

safetyafety

Presented byPresented by

M.GnanasekaranM.Gnanasekaran


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Safety during operation

afety during operation

Keep the work area free from flammableKeep the work area free from flammable

materials.materials.

Ensure that the consumable materialEnsure that the consumable materialis at least 3 meters away from theis at least 3 meters away from the

cutting operation area.cutting operation area.

In case the flammable material isIn case the flammable material isdifficult to remove, suitable fire resistingdifficult to remove, suitable fire resisting

guards/partitions must be provided.guards/partitions must be provided.


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Protect your selfProtect your self

and others from theand others from the

flying sparks.flying sparks.

Ensure that theEnsure that the

metal being cut ismetal being cut is

properly supportedproperly supportedand balanced soand balanced so

that it will not fallthat it will not fall

on the feet of theon the feet of the

operator or on theoperator or on thehoseshoses


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Keep the spaceKeep the spaceclear underneathclear underneaththe cutting job sothe cutting job so

as to allow theas to allow theslag to run freely,slag to run freely,and the cuttingand the cutting

parts to fallparts to fallsafely.safely.


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e careful about flying hot metal ande careful about flying hot metal and

sparks while starting a cut. !ontainerssparks while starting a cut. !ontainerswhich hold combustible substances shouldwhich hold combustible substances shouldnot be taken directly for cutting or welding.not be taken directly for cutting or welding.

"ash the containers with carbon"ash the containers with carbontetrachloride and caustic soda beforetetrachloride and caustic soda beforewelding or cutting and fill them argon gaswelding or cutting and fill them argon gasor water before repairing.or water before repairing.

Keep fire-fighting equipment handy andKeep fire-fighting equipment handy andreadyready


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PROCEDURE AND PRECAUTONS TO !E

ROCEDURE AND PRECAUTONS TO !E

"O##O$ED N OPERATN AS P#ANT

O##O$ED N OPERATN AS P#ANT

#rrange two cylinders in proper position#rrange two cylinders in proper position

$%ertical&$%ertical&

!rack the both cylinder valves before fitting!rack the both cylinder valves before fitting

the regulator, so that all the dirt andthe regulator, so that all the dirt andunwanted material if any may be cleaned out.unwanted material if any may be cleaned out.

'ee that joining surface of the cylinder valve'ee that joining surface of the cylinder valve

and regulators are free from greaseand regulators are free from grease

(it acetylene gas regulator and pressure(it acetylene gas regulator and pressure

gauge to the acetylene cylindergauge to the acetylene cylinder


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!ontent the o)ygen and!ontent the o)ygen andacetylene hoses to theacetylene hoses to therespective cylindersrespective cylindersand the blowpipe toand the blowpipe to

these hosesthese hoses Insert the proper si-e ofInsert the proper si-e of

the tip, after selecting itthe tip, after selecting it

as per the material toas per the material tobe welded.be welded.


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!heck that there is no leakage of gases!heck that there is no leakage of gasesfrom the regulators.from the regulators.

o start the work, turn on the acetyleneo start the work, turn on the acetylenecylinder first and allow the mi)ture ofcylinder first and allow the mi)ture ofthe gases to pass through the no--le,the gases to pass through the no--le,

so that the hoses and blow pipe areso that the hoses and blow pipe arecleared of the air.cleared of the air.

pen the acetylene torch valve slightlypen the acetylene torch valve slightlyand light it which spark lighter. Increaseand light it which spark lighter. Increase

the flow of acetylene till a turbulence isthe flow of acetylene till a turbulence iscreated and the sooty smoke iscreated and the sooty smoke iseliminated.eliminated.


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"#AS%!AC AND

#AS%!AC AND

!AC"REAC"RE

Backfire:Backfire: #t certain times during#t certain times during

flame ignition in gas welding or cutting, aflame ignition in gas welding or cutting, a

small e)plosion of the flame occurs at thesmall e)plosion of the flame occurs at thetorch tip.torch tip.

he flame may or may not go off. his ishe flame may or may not go off. his is

back+fire.back+fire.


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Causes

auses

the gas pressure setting is lowthe gas pressure setting is low

the no--le is over heatedthe no--le is over heated

he no--le orifice is blocked by carbon orhe no--le orifice is blocked by carbon or

spark deposits.spark deposits. he no--le touches the molten poolhe no--le touches the molten pool

here is leakage in the near the no--le.here is leakage in the near the no--le.

liminate the causes before proceedingliminate the causes before proceedingfurther to avoid backfire.further to avoid backfire.


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"las' (ac)

las' (ac)

Flash back:Flash back:

'ome times during'ome times during

backfire, the flame goesbackfire, the flame goes

off and the burningoff and the burningacetylene gas travelsacetylene gas travels

backward in thebackward in the

blowpipe, towards theblowpipe, towards the

regulator or cylinders.regulator or cylinders.his known ashis known as

flashback!flashback!..


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ndications of flas'(ac)

ndications of flas'(ac)

# sharp s0uealing sound inside the# sharp s0uealing sound inside the

blowpipe may be heard.blowpipe may be heard.

2eavy black smoke and sparks2eavy black smoke and sparks

come out the no--le.come out the no--le.

he blowpipes handle starts heating.he blowpipes handle starts heating.


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%*DRAU#C !AC

*DRAU#C !AC

PRESSURE SA"ET* +A#+E

RESSURE SA"ET* +A#+E

It is a cylindrical device which isIt is a cylindrical device which is

used to protect the acetyleneused to protect the acetylene

generator from dangerous flashbackgenerator from dangerous flashbackand backfire, during welding andand backfire, during welding and

cutting.cutting.

It is fitted between the blowpipe andIt is fitted between the blowpipe and

the acetylene generator.the acetylene generator.


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Necessity of 'ydraulic

ecessity of 'ydraulic

safety ,al,e

afety ,al,e

In the low pressure system the o)ygenIn the low pressure system the o)ygen

pressure is always grater than thepressure is always grater than the

generated acetylene gas pressure.generated acetylene gas pressure. 3uring welding, due to backfire or no--le3uring welding, due to backfire or no--le

hole blockage, the high pressure o)ygenhole blockage, the high pressure o)ygen

may enter in to the acetylene passagemay enter in to the acetylene passageand either the acetylene generator, whichand either the acetylene generator, which

will lead to anwill lead to an E"P#$S%$&.E"P#$S%$&.


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o prevent the entry of high pressureo prevent the entry of high pressure

o)ygen or backfire to the generator,o)ygen or backfire to the generator,

a hydraulic safety valve must bea hydraulic safety valve must befitted in the acetylene pipe linefitted in the acetylene pipe line

between the blowpipe and thebetween the blowpipe and the

generator purifier.generator purifier.


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Crac)ed Acetylene

rac)ed Acetylene

%oseose


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Something to think onSomething to think on

Every time you use theEvery time you use the

oxy-acetylene equipment ,oxy-acetylene equipment ,

if certain safety guidelinesif certain safety guidelines

are not followed, it wouldare not followed, it would

be the same as handlingbe the same as handling

live explosives ready to golive explosives ready to go

o.o.

Now lets talk about thegases


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O-y.Acetylene $elding and

-y.Acetylene $elding and

Cuttingutting

E/uip0ent/uip0ent

'EG(#)*$'S'EG(#)*$'S Parts:Parts:

%nlet%nlet Pressure ad+usting screwPressure ad+usting screw

,igh pressure gauge -inside ylinder psi./,igh pressure gauge -inside ylinder psi./

#ow pressure gauge -inside hose to torch#ow pressure gauge -inside hose to torch

psi./psi./ $utlet$utlet


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O-ygen

-ygen

3oes not burn or3oes not burn ore)plode by itselfe)plode by itself

'upports'upports

combustion processcombustion process

)plosive with)plosive with

acetylene, hydrogenacetylene, hydrogen

1ever handle with oily1ever handle with oily

hands or gloveshands or gloves


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Acetylene

cetylene

(lammable(lammable

!ylinder packed with porous material and!ylinder packed with porous material and

solvent that holds the acetylenesolvent that holds the acetylene nce the valve is opened, the acetylenence the valve is opened, the acetylene

flows out in gaseous formflows out in gaseous form

Pressure relief valve using fusible metalPressure relief valve using fusible metalthat melts at about 454 6(that melts at about 454 6(


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Operating data for cutting mild steel

Cutting nozzle

size in mm

Thickness of the plate

(mm)

Cutting oxygen

pressure Kgf/cm

0.8

1.2

1.6

2.0

2.4

2.8

3.2

3-6

6-19

19-100

100-150

150-200

200-250

250-300

1.0-1.4

1.4-2.1

2.1-4.2

4.2-4.6

4.6-4.9

4.9-5.5

5.5-5.6


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Trou(le s'ooting

rou(le s'ooting

Obect Trouble

!art to

beChecked

"ethod #emedy

Torch

$as leakage

%uction of

&cetylene gas

!reheating

flame shape

Cutting

oxygen flo'

ose oint

al*e

+#egulato

r

Cutting tip

attaching

part

,nector

%oap 'ater or

-ater

%oap 'ater or

-ater

%oap 'ater or

-ater

!lug the fuel gas

hose mouth 'ith

your finger

.eutral flame by

*isual inspection

isible gas flo' by

*isual inspection

Tighten further

or #eplace

#eplace the

torch

Tighten further

or #eplace

#eplace

Clean or

#eplace

Clean or

#eplace

gas welding safety

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